Listing 2 myMacAddress method

public byte[] myMacAddress(int networkInterfaceID)
{
    /*  Verify that we obtained a valid networkInterfaceID */

    if (networkInterfaceID < 0 || devices.length <= networkInterfaceID)
        return null;

    /*  Set device to the network interface specified by the 
        networkInterfaceID */

    NetworkInterface device = devices[networkInterfaceID];

    /*  Get the MAC address of the device */

    byte[] returnByte = device.mac_address;

    /*  Convert the MAC address to a string so we can verify we have a
        valid MAC address */

    String macString = "";
    for (byte b : returnByte)
    macString += Integer.toHexString(b&0xff) + ":";

    /*  This function is to fix a problem with the windows jpcap and 
        obtaining a bad MAC address */

    if (macString.equalsIgnoreCase("0:0:0:0:0:0:"))
        returnByte = myMacAddress(0);

    /* return the mac address */

    return returnByte;
}